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Abstract: Two hundred and thirty one isolates, with the characteristic morphology of Genus Bacillus, were recovered from 100 soil samples collected from 7 different Egyptian governorates, and were screened for phospholipase C (PLC) production by egg-yolk plate method. Sixty isolates have shown very high PLC production and were further assessed using chromogenic assay method. The highest five producers, identified by 16S rRNA gene sequencing as Bacillus thuringiensis, were selected and their PLCs were purified to homogeneity using ammonium sulfate precipitation and Sephadex G-75 gel filtration chromatography. PLCs had molecular masses of 28.5 kDa as indicated by SDS-PAGE. The characteristics of the studied five PLCs were having maximal activities at 35-45°C and pH 7.2. The enzymes could retain more than half of their maximum activities at 30-60°C and pH 7-8. Equivalent activities were recorded at low water tension. PLC from B. thuringiensis KT159186 was relatively thermostable with a maximum activity at 40°C. The half-inactivation temperature was above 50°C, which compared favorably to that of other enzymes. Activity at the wide temperature range (20-80°C) was high (about 50% of maximum),. This PLC could tolerate pH as high as 12 with only 30% loss of activity. Specificity pattern of PLC from the same isolate showed equivalent activities toward phosphatidylcholine and phosphatidylinositol in addition to marked activity toward phosphatidylethanolamine, which makes it a typical non-specific PLC for industrial purposes. In conclusion, these characteristics of PLC from the test isolate make it attractive for various industrial applications. Keywords: Phospholipase C, Bacillus thuringiensis, Purification, Chracterization.Download Full Article |
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Abstract: The organic pollutan adsorption/desorption process by microbial degradation had been less studied than metal ones. The sorption assays alone did not predict desorption, due to hysteresis, irreversibility, fixed compounds in different sites, with diverse desorption rates. Most of the studies dealt with bacteria rather than filamentous fungi and yeasts. So, our aims were to isolate yeasts from polluted sediments, to quantify its potential to uptake anthracene (An) and to evaluate the bioavailability by a desorption model. Yeasts were isolated from hydrocarbon-polluted samples, 40-isolates grew in anthracene-plates. Molecular characterization was achieved by sequence analysis of the ITS1-5.8S rRNA-ITS4 and 26S rRNA regions; morphological and physiological determination were also done. Candida parasilopsis, Pichia anomala and Rhodothorula mucilaginosa were the prevalent yeasts. An-degradation was assessed in soil-systems with 0, 50, 100, 150, 200 and 250 μg An/l, 3 differentes sorbens types, organic carbon, organic nitrogen, PAHs, sand:silt:clay, pH and cation exchange capacity. Sophorolipids excretion were confirmed by HPLC, UV-detector with active fraction at 9.669 min (RT 9.646 min = sophorolipid-standard). A desorption model with equilibrium, nonequilibrium and nondesorption areas, was applied to explain the experimental data, An-transformation was greater in the organic liquid-phase than in the soil-sorbed ones; the desorption-coefficients and soil components were negatively correlated with the kinetic parameters. The An-release depended on the sophorolipid excretion, soil matrix and particles sizes. Desorption parameters significantly fitted the yeast uptake, with R2 = 0.97, R2 = 0.90 and R2 = 0.97 for C. parasilopsis, P. anomalaand R. mucilaginosa, respectively. Keywords: Anthracene, bioavailability, biodegradation, Candida parasilopsis,desorption model Pichia anomala, Rhodothorula mucilaginosa, sophorolipid.Download Full Article |
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Abstract: L-DOPA (L-3,4-dihydroxyphenylalanine) the precursor of neurotransmitter dopamine is used in the management of Parkinson disease and effective in controlling diabetic state. Gamma-aminobutyric acid (GABA), a non-protein amino acid is known to have many pharmacological functions and plays a major role in inhibiting neurotransmitter in brain. Whereas essential amino acids can’t synthesize in human body and it must be taken from foods to maintain good immune function. This study aims to evaluate the enrichment of mung bean with L-DOPA, GABA and essential amino acids via controlled solid state fermentation using Rhizopus strain 5351. Fermentation was carried out for a duration up to 48 h at 30 °C and the samples were analyzed at certain time intervals. The concentration of glucosamine and β-glucosidase, which indicated the growth of fungal was noted low at the early growth stage (0 to 10 h), but it was observing increased linearly within 18 to 48 h growth periods. The L-DOPA was produced after 10 h fermentation time (0.008 g/100 g dry weight, DW) and the highest yield of L-DOPA content (0.07 g/100 g DW) was attained at the fermentation time of 28 h. However, the concentration of L-DOPA was noted decreased after that. The protease activity, free and essential amino acids content also showed a drastic increment within the fermentation period of 10 to 38 h. The highest content of free and essential amino acids (FAAs and EAAs) and the protease activity of fermented mung bean were exhibited at 38 h incubation time, which were 3.74 g/100 g DW, 1.43 g/100 g DW and 18.4 U/g dry weight, respectively. The GABA content of fermented mung bean was found low (0.019 - 0.021 g/100 g DW) at early incubation time (0-10 h), however, it showed a drastic increment in the fermented mung bean after 18 h (0.132 g/100 g DW) and continuously increased until 38 h (0.198 g/100 g DW). This study showed the potential of solid state fermentation as a good strategy to enrich the fermented mung bean with L-DOPA, GABA and other beneficial bioactive compounds which play an important role to maintain good health as it helps to enhance our immune system and regulating neurotransmitter function. Keywords: L-DOPA, GABA, Mung Bean, Protease, Solid State Fermentation.Download Full Article |
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Abstract: The impact of polymer concentration and drug loading on nanofiber morphology and diameter were investigated during electrospinning of polyhydroxyalkanoate nanofibrous films. Low molecular weight poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-95 mol% 4HB)] required a 5-fold higher solution concentration than high molecular weight poly(3-hydroxybutyrate) [P(3HB)] to produce bead-free nanofibers. Loading the films with paclitaxel increased the initial polymer solution viscosity allowing larger diameter nanofibers to form. Furthermore, paclitaxel added at 1% (w/w) into 8 % (w/v) P(3HB-co-95 mol% 4HB) solution eliminated the formation of beads seen in solutions without the drug, at the same initial polymer solution concentration. In preliminary drug release studies, nanofiber mats consisting of large-diameter nanofibers with high drug loading released paclitaxel at a faster rate due to larger pore sizes. This was a consequence of the random packing of larger diameter nanofibers. However, the release pattern of nanofibers with low drug loading was much more consistent and controlled. Lastly, we have shown the potential applications of P(3HB-co-4HB) drug loaded nanofibers in the development of biocompatible drug eluting stents by directly coating a metal stent with a homogeneous layer of electrospun polymer. Keywords: polyhydroxyalkanoate, electrospinning, nanofibers, drug loading, biocompatibility.Download Full Article |
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Abstract: A large amount of oil hydrocarbons and heavy metals have been discharged into the environment and caused soil polluted. Petroleum and cadmium in soil accumulated in crops and lead to threaten human healthy through the food chain. In this experiment, seeds of sorghum and rape were germinated in deferent concentrations of petroleum and cadmium, and the effect of Peptococcus activus sp. SH3-3-9 on the germination was studied. The results showed that petroleum and cadmium inhibited seeds germination, and the effects were stronger as their concentrations increased. Peptococcus activus sp.SH3-3-9 had the role of enhancing seed germination, which indicates it has high potential in plant-microbial remediation of petroleum and cadmium in soil. Keywords: Bacteria, cadmium, petroleum, sorghum, rape.Download Full Article |